This invention relates to fluid flow control clamp systems and methods for controlling fluid flow. More particularly, the invention relates to such clamp systems and methods useful for controlling fluid flow rates in flexible conduits, e.g., tubing in intravenous systems.
Intravenous or IV systems are very important in caring for medical patients. Such systems are extensively used to provide one or more needed fluids, e.g., liquids, directly to the patient's vascular system. Of course, very careful control of the flow rate of any fluid passing into the patient's body is desirable. However, such control has been difficult to obtain.
Some of this difficulty results from the fact that the flexible conduit or tubing from the fluid source to the patient's body is small diameter. Also, the flow rates through such tubing are often relatively small. Flow control clamps currently in use are costly and/or structurally complicated and/or may not provide adequate control precision.
In preparing this application, the following U.S. Patents were considered: U.S. Pat. Nos. 2,215,725; 2,314,767; 3,948,477; 3,993,076; 4,106,508; 4,337,791; 4,475,709; and 4,482,347. Of these patents, both U.S. Pat. Nos. 3,993,076 and 4,106,508 disclose clamp devices for completely occluding blood vessels or other tubular conduits in animal bodies which involve resilient surfaces to reduce trauma caused by the complete occlusion. Devices disclosed in the other above-noted patents which relate to intravenous tubing do not include resilient surfaces since trauma caused to such tubing is of little or no concern.
Peristaltic pumps by necessity involve repeated opening and complete occlusion of a fluid containing conduit. In one particular such device, i.e., sold under the trademark AccuPro by Kendall McGaw of Irvine, Calif., rollers act to contact the periphery of the conduit with the conduit's periphery opposite the rollers contacting a resilient element. The action of each of these rollers causes the conduit to range from being open to being completely occluded, with no one degree or state of occlusion, e.g., partial occlusion, being maintained for any substantial period of time. Collectively, the rollers act on the conduit to provide the desired pumping action to the fluid in the conduit. With the rollers stopped, no fluid flows through the conduit.